"Life must come first," said Gillian Ayres, one of Britain's foremost abstract artists, explaining why last week she tendered her resignation from the Royal Academy. "Those murders will always be remembered, like Jack the Ripper's. When you think of the parents, you hardly want to enhance the whole thing for them."

Ayres, 67, was speaking of the academy's decision to include Marcus Harvey's portrait of the killer Myra Hindley in its new exhibition, Sensation. It was a decision that caused the resignation in protest of the sculptor Michael Sandle, and led to two sabotage attacks on the work when the exhibition opened to the public on Thursday.

A renowned painter whose own work was celebrated in an RA retrospective earlier this year, Ayres finds herself in an uncomfortable position. She has no wish to judge other artists and yet she feels "in my gut" that something is very wrong.

In the end, though, it was not just the inclusion of Harvey's image of the Moors Murderer picked out in child's handprints that pushed her into action. It was a television programme, an Omnibus account of the preparations for the exhibition.

"That BBC film on Sunday night showed such an unfair view of the older members. The academy should never have let them do it," she said.

The unflattering treatment of her former tutor, the elderly artist Victor Pasmore, was particularly upsetting for Ayres. "I wasn't happy about the Myra Hindley painting, it's true, but what made me go was that film on Sunday.

"Pasmore was shown just because of his age, but at one time he was a really good painter.

"It seemed to me that the people at the academy have got into a slightly inhuman state of mind."

Ayres's initial intention had been to keep out of the debate entirely. "I stayed away at first, but then it all grew into an argument and I thought, well, rather than simply staying away I ought to resign. I thought it was more honest."

Her honesty has not been appreciated by some of the young artists exhibiting in Sensation.

"It is ridiculous for her to resign," said former Turner Prize contender Gary Hume, who has six works on display in the new show. "You can buy pictures of Myra in books in W H Smith anyway. It is a totally public image now. I do feel very sorry for the parents of victims, but I don't see what is shocking about the exhibition at all."

Sensation displays 110 works from the advertising mogul Charles Saatchi's collection of contemporary British art. In an attempt to chronicle the new wave, it includes Damien Hirst's notorious shark in formaldehyde and a work by Jake and Dinos Chapman in which naked mannequins offer up swollen male genitalia.

Artistic shock tactics like these do not bother Ayres. What has troubled her, though, is the direct emotional appeal from Winnie Johnson, whose 12-year-old son was one of the Moors Murders victims. For Ayres, Mrs Johnson's reaction to Harvey's work is important and entirely understandable.

"As far as the Hindley painting goes, while I didn't really resign over it, I do feel for the parents. I haven't seen the painting and in a way I don't think it is a question of how good it is. That would be a form of censorship. I think it is a question of taste."

Ayres, who lives on the Devon/Cornwall border with the artist Henry Mundy, is not dismissive of all the work displayed in Sensation. "Some of the works are clearly good," she said. "You can't say it is a simple argument, because someone like Rachel Whiteread is clearly a good artist. I am certainly interested in them all and that counts for something.

"It is just that it is hard for a creative person to belong to an establishment. What is more, because the academy is seen as the establishment, that makes it much more hurtful to the victims' families. If it was just some small gallery somewhere it would not be the same."

For Hume the whole debate is merely another irrelevant episode in "the mad English obsession" with the question "What is art?"

"Only a few people have decided that this painting is the shocking thing about the exhibition. If it was not Myra it would be something else.

"Rather than resign, painters should look to their own art for their response to all this."